Another way to do it is access through your DH web admin panel using your web browser as you normally would.

If you go to the “Manage” subsection of “Domains,” you’ll see a option that says “Upload To Site.” You’ll be prompted for your password and then it’s simply a matter of dragging files from your computer into the ftp folder you pick. (At least that’s how it works for me - I’m on a Windows system).